Friday, November 9, 2007

What Can Evolution Do?

Malaria is the million person Murderer; it kills 1 million people each year, and makes 100 million other people sick. In some regions, it kills half of all children before the reach the age of 5. It is like Dracula, feeding on blood. It is carried by mosquitoes, and transmitted when they bite. Once inside a person they keep feeding until they reach the liver, where they stop to multiply. It attaches to a red blood cell, goes inside puts a protective covering on and feeds on the hemoglobin. The infected blood cell gets stuck in our veins and stops circulating. Malaria reproduces until about 20 copies are made, they then break out of the now trashed red blood cell and re-enter the bloodstream to go into more red blood cells. They multiply exponentially, so that within a few days there are a trillion new malarial parasites, which consume a large portion of the victim’s blood. Because they are so numerous, and it has been studied so much, it is the best example of what evolution can do.

The modern fight against malaria began in South America with the discovery that bark from the cinchona tree was useful for treating the fever. Quinine is developed from the cinchona bark, and once it was discovered in the 17th century that it could be used as a cure for malaria. But in the 1940’s the active ingredient was isolated, and a compound developed called ‘Chloroquine’ that was even more effective against malaria. Because Chloroquine was effective, with few side effects and inexpensive to make it became the drug of choice for treatment of malaria for decades.

Malaria has 14 chromosomes, and the resistance part was recently discovered to be part of a 400,000 nucleotide region of one chromosome. It was further narrowed to 36,000 nucleotide region. The complexity of even a simple parasite like malaria is mind-blowing. The DNA for malaria encodes 5,300 proteins (proteins are essential to the operation of the cell, participating in every process of the cell. This includes being enzymes for metabolism, structural and mechanical functions – like forming the cell structure and building muscles, cell-signaling, immune responses and cell adhesion.) The PfCRT protein (for P. falciparum, a malaria species - Throughout my post when I use ‘malaria’, it is for P. falciparum) normally has 424 amino acids in a strict sequence. When there is a change in the amino acid sequence, the change commonly happens at position number 76 and 220. These mutations are what have provided malaria’s resistance to Chloroquine. This is what evolution can do in making an organism more resistant to an enemy like Chloroquine that is designed to destroy malaria.
So these two mutations at spot 76 and 220 of the amino acid sequence are what Darwinism can do – they provide resistance to the primary drug used to fight malaria; Chloroquine. Remember, that there are 1 trillion malaria cells in an infected person. And there are over 500 million people infected each year. Tom’s Important Point: So with so many malaria cells (1 trillion in a sick person) and so many people infected with malaria (500 million each year), how often does a simple double mutation of the amino acid sequence happen to provide resistance to the top drug used to fight Chloroquine? One researcher has estimated that it has only happened 10 times over the past 50 years.

Resistance to Chloroquine has only appeared 10 times in the whole world in the past 50 years (!!!). And so, one writer estimates that if you count the number of malaria cells in a very sick person times the number of people who get malaria each year times the number of years since Chloroquine was introduced, we see that the odds of a parasite developing resistance to Chloroquine is roughly one in a hundred billion billion. Written in shorthand this is 1 in 10²⁰. Most of the information in this post is from Prof. Michael Behe’s recent book: The Edge of Evolution. My background is not in science, and so if you find anything that needs to be corrected, please be gentle. Your first course in molecular biology is now concluded.

3 comments:

Bryan & Meggan said...

Wow! I'm glad I don't have to be a science guy. Fascinating.

-- Bry

Edward Oleander said...

Hi Tom,

Some of your numbers need some revision. The P. falciparum you use is only one of four known malaria bugs. The info I found (based on numbers from the CDC and WHO) just happened to refer to that strain, as well as P. vivax.

"The location where a person gets a malaria infection helps a doctor decide which malarial medications to use for treating the infection. For instance, P. falciparum is resistant to:

* Chloroquine in all countries with P. falciparum malaria except Haiti, the Dominican Republic, Central America west of the former Panama Canal Zone, Egypt, and some countries in the Middle East.
* Both chloroquine and pyrimethamine-sulfadoxine (Fansidar) in Thailand, Myanmar (Burma), Cambodia, the Amazon River basin, and parts of east Africa.
* Mefloquine in those areas of Thailand where malaria infections occur, as well as western Cambodia and eastern Myanmar.
* Quinine in Southeast Asia, especially in the border areas of Thailand.

P. vivax medication resistance

P. vivax is resistant to chloroquine in Indonesia, Papua New Guinea, the Solomon Islands, and Myanmar."
http://www.questdiagnostics.com/kbase/frame/aa484/aa48489/frame.htm

This proves that FAR more than 10 cases of resistance have been shown. I don't where Behe got his "10" from, but it was quite clearly wrong. I find this exaggeration typical of Behe's "science."

From his conclusions, it also appears that Behe is ignoring some important facts regarding the immune system. Resistance builds slowly. Especially in the early stages of resistance building, there will not be either/or cases. At first their is limited resistance. In MOST cases, resistant bugs of all kinds are successfully killed by the your own immune system. RIGHT NOW you have drug resistant bugs IN YOU, but you will likely never know it because the macrophage "Killer T" cells of your immune system are (and will continue to be) enough to keep them in check. These bugs come to us in our food, in our air, and by physical contact EVERY day... The immune system is transparent enough that Behe CANNOT know how many true cases of resistance there have been. You point out that 1 trillion malaria bugs grow in an infected person. Even if you look at 1 million individual germs in one single person, you are getting a sample size of only 0.0001%. You're going to miss a lot of the picture. That is why research so often seems slow to us; it takes a LOT of time to build really good data.

Let's assume that Behe is right, and malaria just seem to get around the chloroquine problem. Now correct me if I'm wrong, but you (and Behe) seem to believe that Malaria's lack of progress against chloroquine proves that it is not evolving, and by extension, nothing else is either. A classic Hasty Generalization, and easily refutable thus:

If I am standing near Ground Zero in Hiroshima at the right moment in history, I will most certainly die in an atomic flash. So will all the other humans (and other living things) in my vicinity. Does this prove we are not evolving? Or does it merely prove that all us dead people failed to adapt quickly enough to the sudden change in the local environment? Some environmental changes are extremely difficult to overcome. Chloroquine is not an A-Bomb, but is nearly as devastating to malaria. Resistance is difficult, and thus rare, but only proves that most of the bugs cannot adapt or cope with the new environment. The argument cannot be extended beyond it's immediate circumstance.

Behe could have chosen other bug vs. drug relationships. Many germs easily overcome some drugs, but continue to fall to others. All germs have strengths and weaknesses. One CANNOT extend a weakness in one bug to a conclusion that the bug has reached (or was always at) a dead end.

Think I'll do my own blog, Eddie's Evolution Emporium, just so you can have equal time... Shalom!
~E~

tom wolff said...

Hi Ed,

you said: "...This proves that FAR more than 10 cases of resistance have been shown. I don't where Behe got his "10" from, but it was quite clearly wrong. I find this exaggeration typical of Behe's "science."

You are off-base in claiming Prof. Behe has exagerrated anything in his book. I don't know why you would even make such a wild, unsupported attack when you haven't even opened or read his book (?!) Anyway, what Prof. Behe has done is taken a look at ALL of the studies on malaria, and shown what the scientific studies are reporting.

So, yes, Prof. Behe cites many studies on malaria throughout his book. The one times ten to the 20th power estimate for malaria's odds of developing resistance to chloroquine came from N.J. White of Mahidol University in Thailand(2004), 'Antimalarial drug resistance' published in J. Clin. Invest. 113:1084-92. So of course, there is no exaggeration by Prof. Behe, only his reporting of what the scientific journals have reported.

I know you are zealous to try and protect your sacred cow of evolution. But before you waste everyone's time with arguments without much thought or any support, why don't you put in some research first. Thanks.